Traditional water beds generally lack stability when a person lies on it, as the water is liable to move around inside the plastic bag as he/she moves his/her body. However, this water movement does provide a cooling action to the user in hot weather. To decrease the swaying movement of water beds, there has been disclosed the using of a layer of foam rubber or floating balls inside the plastic bag. However, the improvement is only marginal. In fact, such water beds may have more movement in other directions.